This invention relates to breathing bag systems for a closed circuit breathing apparatus and more particularly, to breathing bag systems for use with breathing hoses, a chemical oxygen generator and a carbon dioxide absorption system.
In the event of a fire, a factory accident, a coal mine accident or an oxygen deficiency accident, an antitoxic mask is not effective for protecting the user. To provide a personal breathing apparatus effective under such circumstance, various types of breathing apparatus comprising a self-contained oxygen source have been proposed. Most of them utilize an oxygen bottle or a compressed air bottle as an oxygen source. Although oxygen bottles are more often used because they supply high-purity oxygen gas quite handily, they must be handled and stored with special care. Also, both oxygen and compressed air bottles are heavy, resulting in a heavy and unnecessarily sturdy overall structure for a personal breathing apparatus. Thus, people wearing a breathing apparatus having an oxygen bottle are not able to move quickly to escape in an emergency or to take action in an accident.
On the other hand, it is also known to use a chemical oxygen generator as a source of oxygen. Although a chemical oxygen generator is light in weight and easy to store, it has not been successfully put into practical use mainly because of initial difficulties in obtaining a chemical oxygen generator having a satisfactory performance. Although many high-performance oxygen generators have recently been developed, these generators have not yet been successfully utilized for a personal breathing apparatus. The reasons for this are believed to be (1) that it is difficult to supply oxygen at a stable rate because of the varying oxygen generation rate of these devices, and (2) that it is difficult to cool the generated oxygen gas, which is very hot because of the massive dissociation heat generated during the oxygen generation, to a temperature at which it is safely breathable by the user.